A significant fraction of power in a secret signal component of a navigation satellite signal such as a Global Navigation Satellite System (GNSS) signal may be lost when the GNSS signal passes through band pass filters used by a GNSS client device (receiver). The loss of power degrades performance in low signal-to-noise-ratio (SNR) environments. Degraded performance in low SNR environments may prevent or minimize an ability of an authentication system to validate that a global position computation or an assertion based on a global position is bona fide.